Chemical process and products



Patented July 31,1945

zsaoau EN'r-I os cs cimmcsr. raocsss Asp monuc'rs a Horace 8.Isbell,W

n, D. 0., assignor to ashingto the Government 01' the United States, represented by the Secretary ot-.Commerce No Application September 4.1m;

Saris-1N0. sous: a

s Claims. (c1. sec-4w (Granted under the act a! March 3, 1888,

amended April 80, 1928; 8'10 0.-'G. 75'!) This i'nvention'relates to the manuiacture of la, 01111401, and has a melting point or 156 'de-' new chemical compounds and more particularly to the manufacture of crystalline derivatives of galactonic acids.

oi galactonic acids.

The above and other objects hereinafter apparent are accomplished in accordance with the present, invention which provides crystalline methyl esters of galactonicacids by subjecting toreactionat a temperature between 20 degrees C. and 100 degrees C. a mixture or methanol and a salactonic compound from the group consisting for L-galactonic acid, D-galactonic acid, and lactones thereof, and recovering an ester of a galacgrees C. In 4 percent aqueous solution, the specific rotation of the. product is 11.

Example 2 methanol and adding ether to the saturatedsolution.

tonic acid. It has now been found that the methyl esters or galactonic acids can readily be prepared in accordance with thepresent invention, andthat such esters can be crystallized in a pure state to provide a simple procedure for purifying salactonic acidiromcrude mixtures containing The invention will be made clear by reference to the following illustrative examples which show how the invention may-be carried out, but it is not restricted thereto. Parts are by weight unless otherwise designated and the parts by weight bear the relation to parts byfvolume that obtains between the gram and the milliliter.

v Emple 1 Ten parts of D-s'alactonic acid isadmixed, in a glass reaction vessel provided with a reflux condenser, with 200 parts by volume of methanol and r 3'parts' of hydrogen chloride. The reaction mix ture is heated over a steam bath for two hours under atmospheric pressure to the boiling point, a gentle refluxing-being maintained. 'Ihereupon, the hydrogen chloride is precipitated'by the addition of silver carbonate, and the precipitated aqueous solution. By

The new compound exhibits a melting point of 156 C. and a specific rotation of 11-, in 4% analysis, the formula corresponds toCvHuO's.

Emmple 3 Twenty parts of galactonic gamma-lactone are heated at 50 C. with 75 parts of anhydrous methanol and 1. part of dimethyl sulfate, in a glass reaction vessel, provided with means ior excluding atmospheric moisture, In the course or several hours, methyl galactonate crystallizes from solution. The crystals are separated'i'rom the mother liquor by,filtration and purified asdescrlbed under Example 2. The mother liquor is heated with -additional salactonic gamma-lactone and methyl alcohol, for the preparation oi. additional ester.

'I'hecrystals are repeated.

separated and the cycle can be It will be apparent from the foreso ing'descrip- I tion and examples that new crystalline compounds of both D-salactonic acid and 11988181501116 acid silver chloride with excess silver carbonate is 1712-:

" moved by filtration from the reaction mixture.

The filtrate. is subiected to evaporative crystallilation by gently heatins. and crystalline methyl- I in a .yieldapproachina quantitative The crude ester is sap-I aratediromthcgnotherliqitorbyfiltaticmand recrystallised 'irom acetone. 'Ihe recrystallization is, hastened by adding limih to thescetone The product corresponds t'othe have been provided. They'can be prepared by the esterification oi the D- or L- acids and lac- I tones with equal facility. They readily separate as distinct crystalline entities, and are easily purified. Thus, the invention provides a very desirable esterificaticn method' for purifying galac- 'to ic acid 'irom crude containing it, and the ester which is'prepared can-readily be hydrolised in the presence oi excess water to liberate asain the pure alactonic acids.

Since many apparently widely difiering embodiments oi the invention will occur to oneskilledintheart.variouschanscscanbemade.. intheinvcnticnwithoutdepartinzimmthespirit described herein may be;made i'ormu-u andusedbyandtorth'cGovernmentoithcUn ited The invention of any royalty the group of L-galactonic acid, D-galactonic acid,

and lactones thereof, and recovering a, crystalline ester of galactonic acid.

5. In a process for the production oi a purified galactonic compound from crude mixtures containing'the same, the steps which comprise treating a crude mixture containing a compound from the group of galactonic acids and their lactones with methanol and an esterlflcation catalyst, then crystallizing and separating a relatively pure monomethyl galactonic ester from the impuritycontaining solution.

' HORACE S. ISBELL. 

